The present invention relates to an apparatus for holding a trocar sleeve in different spatial orientations relative to a patient, comprising a base member fixedly positionable relative to the patient and a retainer for the trocar sleeve, where the retainer is connected to be tiltable with respect to the base member by a flexible connecting member.
A holding apparatus of this type is disclosed in U.S. Pat. No. 5,540,675.
A trocar provides access into the body in minimally invasive surgery. A small incision can be made with a trocar mandrel, through which incision the trocar sleeve is inserted into the body of the patient. The trocar mandrel is subsequently withdrawn from the trocar sleeve. The trocar sleeve thus forms an access channel into the body of the patient.
Trocars are used particularly in minimally invasive surgeries in the stomach region, the field of laparoscopy. Its use however is not limited thereto. Medical instruments can be reliably guided and held in the channel formed by the trocar sleeve and, in addition, the channel serves to supply or discharge fluids or gases into or out of the patient""s body. For this purpose, a flap valve housing is usually provided at the proximal end of the trocar sleeve with corresponding sealings and stop cocks.
The trocar sleeve is located in a spatial orientation corresponding to the incision channel. The trocar sleeve however can be varied in its orientation by hand; it returns to the direction of the incision channel when the tube is released. This results from the tendancy of the tissue layers penetrated by the trocar to realign themselves to a certain position. For this reason, apparatus of the above-mentioned type are used to hold the trocar sleeve in certain positions.
One or more different spatial orientations of the trocar sleeve is desirable during a surgery. In a first operational state, the holding apparatus retaining the trocar sleeve is slightly adjustable. Once the trocar sleeve is oriented in the desired position, it should no longer change its disposition. In a second operational state, the holding apparatus is rigid and the trocar sleeve remains fixed in the selected spatial orientation.
The holding apparatus disclosed in mentioned U.S. Pat. No. 5,540,675 comprises an annular base portion which is directly secured to the patient""s body with an adhesive layer. The annular base portion is connected with elastic, rubber connecting members to a retainer arranged centrally with respect to the base portion and in the starting condition perpendicular to it. The retainer in the present case itself is tube-shaped. The trocar sleeve is inserted into the retainer. To orient and to fix the retainer in different directions with respect to the base portion, a telescopic-like tensioning mechanism is provided consisting of at least one tensioning element adjustable in length. It is secured between the radially outward region of the base portion and the end of the retainer lying remote from the base portion. The inclination of the retainer relative to the base portion can be varied by adjusting the length of the tensioning element. However, it is first necessary to release the tensioning element with a screw, to adjust the tensioning element to the desired length and finally to again tighten the screw. In one embodiment of the known holding apparatus, three tensioning elements in the form of a tripod are arranged about the retainer for reasons of stability. The trocar sleeve can only be tilted in one single plane with one tensioning element. The adjustment and securement of the desired position of the retainer is complicated in this known holding apparatus. To change the spatial position of the trocar sleeve, all three tensioning elements for fixing the retainer must first be released, and then adjusted and finally retightened. Should the operator after inserting an instrument, for example an endoscope, find that the orientation is not yet exact, he must again carry out the complicated procedure. Extremely tilted positions of the trocar sleeve are not achievable in a stable manner due to the tripod geometry.
Furthermore, the tensioning elements of this known apparatus comprise numerous bacterial niches, cavities and corners, for example the threadings of the adjustable screws and the telescopic shafts, so that the known apparatus is difficult to clean and to sterilize.
Another type of apparatus for aligning and fixing medical instruments is described in the U.S. Pat. No. 5,597,146, which is representative for numerous similar arrangements. This type of apparatus comprises a multi-link pivot arm, whose individual link elements can be oriented independent from one another about different axes. A medical instrument to be fixed can be positioned and held at an arbitrary position, similar to a robot arm. This type of apparatus however is very complicated with respect to its construction and manufacture. In addition, it takes up space on the operating table above the patient and thus obstructs the surgeon""s access to the patient from several directions.
It is, therefore, object of the present invention to provide an apparatus of the mentioned type, which is simple to operate and enables a rapid and at the same time reliable adjustment and fixation of the spatial orientation of the trocar sleeve relative to a patient.
This object is achieved in that the connecting member has a first operational state in which it is flexible and a second operational state in which it is rigid and in that the connecting member is switchable between the first flexible and the second rigid operational state.
The apparatus according to the invention does not require telescopic-like or column-like tensioning elements held with screws, whose handling is cumbersome and complicated. The invention instead provides the degree of flexibility or of rigidity of the flexible connecting member to be variable itself. It is therefore possible in a first operational state, where the connecting member is flexible, to align the trocar sleeve and also the medical instrument therein in the desired position. By switching over to the second operational state where the connecting member is rigid, the trocar sleeve is then fixed in the adjusted position.
The realization of a connecting member with two such different operational states is technically possible in different ways. Preferred manners of realization are correspondingly described in the following with reference to the dependent claims.
The apparatus according to the present invention has the advantage that the adjustment and fixation of the trocar sleeve position and therefore the medical instrument passed therethrough, is easily possible in any, even extreme tilted position in the first flexible operational state, while the adjusted position is safely and reliably held in the second rigid operational state. Compared to the known apparatus, the present apparatus is much easier to operate. At the same time, it is possible to place the present apparatus with its base directly adjacent to the patient to be treated, for example on his abdominal wall. This has the advantage that the apparatus and therefore the trocar sleeve held therein follows changes in the position of the patient. An undesired relative movement of the trocar sleeve with respect to the patient is avoided. Finally, the present apparatus requires very little space, so that access to the patient from different sides is not obstructed.
The connecting member comprises an elastic casing filled with a material having variable rigidity. This feature has the advantage that the material can have the properties of a flowable mass in the first operational state, because the material is contained by the elastic casing. With this, a particularly simple adjustment of a given spatial orientation of the trocar sleeve is possible. Furthermore, this feature has the advantage that the apparatus has a uniform and smooth surface, due to the elastic cover, preferably of silicone, which is simple to clean and to sterilize. In the second operational state, the rigid mass then holds the trocar sleeve fixed in the desired spatial orientation.
In a further configuration, the material is a particulate material and the apparatus comprises means for generating a vacuum within the casing. In this configuration, the connecting member of the present apparatus is comparable to a balloon filled with a sand-like material. As long as the balloon casing additionally contains air or another gas, the material in the interior is formable. Correspondingly, this is the first operational state in which the connecting member is flexible.
By creating a vacuum in the casing, the air is suctioned out of the balloon, the particles are pressed against one another and the material loses its formability. The connecting member is rigid in this second operational state. The mentioned feature therefore represents a very simple technical possibility of realizing a connecting member where the operational states according to the present invention.
Furthermore, this embodiment has the advantage that the switching between the first flexible and the second rigid operational state is very rapid and simple with the aid of a valve and a pump. In addition, the necessary means for generating a vacuum are known per se in the field of clinical instruments and are also employed there. The present apparatus thus can be realized particularly inexpensively as a supplement to existing devices. A further advantage of this configuration is that the switching between the first flexible and the second rigid operational state is possible xe2x80x9csimply by pushing a buttonxe2x80x9d and if desired can be completely automated.
In a further embodiment, the surface of the particles of the material is configured such that the particles in the closely compressed condition are prevented from sliding past one another and therefore form a rigid mass. This is particularly the case when the particles have edges, so that the individual particles lie immovably upon one another or catch within one another in the pressed form. The feature has the advantage that a particularly high rigidity of the connecting member is achieved in the second operational state.
In a further embodiment, the material with adjustable rigidity is a fluid whose viscosity is adjustable between being elastic and rigid. Such materials are known per se in the prior art. They have a molecular structure where the molecules in different operational states are varyingly strongly coupled to one another and/or oriented with respect to one another. This leads to the fact that the fluids have differing viscosities in different operational states. This feature has the advantage that a very simple and fast reacting possibility is given to realize a connecting member according to the invention with the desired operational states.
In a further embodiment, the viscosity of the material is adjustable in response to an electric and/or magnetic field. These are electric or magnetic viscous fluids, whose molecular structure changes under the influence of the mentioned fields. Alternatively, fluids are known whose viscosity changes depending on pressure. This has the advantage that switching between the operational states according to the invention is very simple and xe2x80x9coccurs practically by pushing a buttonxe2x80x9d or when needed can be completely automated.
In a further embodiment of the apparatus, the connecting member comprises a material, which is flexible at a first adjustable operational temperature and is rigid at a second operational temperature. Preferably, the second operational temperature is room temperature, where the present apparatus is normally used. The mentioned feature represents a further, alternative possibility of realizing an apparatus with the connecting member according to the invention.
In a further embodiment, the connecting member is a torus-shaped body with the retainer being arranged in its opening. The feature has the advantage that the connecting member is arranged to surround the retainer and thus guarantees a flexibility or rigidity uniformly in all directions. In addition, a particularly high stability of the apparatus is achieved in the second operational state.
In a further embodiment, the base member is secured to a support frame, which can be adjustably and fixedly mounted to an operating table.
Alternatively, it is also contemplated to fix the present apparatus directly on the patient""s body, either alone through its own weight or additionally by using a releasable adhesive. The former feature however has the advantage that the base and thus the entire apparatus can be held substantially more stable and secure with respect to the patient. It is insured that the apparatus is not inadvertently shifted through movements of the patient. At the same time it is ensured that the apparatus can always be positioned optimally with respect to the patient due to the adjustable, but fixed mounting on the operating table.
In a further embodiment, the support frame comprises at least one rail extending over the operating table, preferably in about the transverse direction with respect to the patient. The feature has the advantage that particularly good stability is achieved without the apparatus requiring too much space and obstructing access to the patient. In addition, such a rail can be arranged in simple manner such that the base member of the apparatus lies practically directly on the patient""s body, where relative movement between the trocar sleeve and the patient is substantially excluded.
In a further embodiment, the base member is secured to the rail to be slidable. The feature has the advantage that the holding apparatus can be adjusted rapidly and in simple manner, and thus can always be disposed at the optimal position with respect to the patient.
In a further embodiment, the at least one rail along the operating table is shiftable and/or pivotal about a pivot point.
These features also contribute to enhancing the possibilities of use and the positioning capability of the present apparatus. At the same time, the operation of the apparatus is very simple and the apparatus does not represent an obstacle for access to the patient. Furthermore, compared to the variably adjustable, multi-link pivot arm, the embodiment is simple and inexpensive in construction and manufacture. In a further embodiment, the support frame comprises several rails, on which several base members with retainers and connecting members are secured. The advantage is that the stability of the apparatus is improved when using more rails. The use of several base members also has the advantage that several medical instruments can be fixed at the same time at different positions on the patient.
It will be understood that the above-mentioned features and those to be discussed below are applicable not only in the given combinations, but may also be used in other combinations or taken alone without departing from the scope of the present invention.